Please try to read my earlier comments. In the absence of a proper example with expected output I think what you are trying to achieve is:
# create a sample dataframe df <- data.frame(Command=c("_localize_PD", "_localize_tre_t2", "_abdomen_t1_seq", "knee_pd_t1_localize", "pd_local_abdomen_t2")) # identify which rows in the dataframe set match the patterns # note, the vectors PD, T2 and PDT2 are booleans indicating if a match was made PD <- grepl("pd", df$Command) T2 <- grepl('t2', df$Command) PDT2 <- grepl("(.*t2.*pd.*)|(.*pd.*t2.*)", df$Command) # create the new column to hold the new names df$new_name <- NA df[PD,'new_name'] <- 'pd' df[T2,'new_name'] <- 't2' df[PDT2,'new_name'] <- 'pdt2' # note 1: the order of these command is important, if the last command is run first all matches will be overwritten by the single matches for 't2' and 'pd'. # note 2: There is no match for row 1 as "PD" != "pd", as suggested by John McKown the ignore.case parameter for grepl can be used to change this behaviour. On Mon, May 2, 2016 at 11:01 AM, <chalabi.el...@yahoo.de> wrote: > I just changed all the names in Command to lowercase, then this > str_extract works fine for "pd" and "t2", but not for "PDT2". Do you have > any idea how I can bring PDT2 also in str_extract? > > > On Monday, May 2, 2016 9:16 AM, Tom Wright <t...@maladmin.com> wrote: > > > > The first thing I notice here is that your first two subset statements are > searching in an object named Command, not the column df$Command. I'm not at > all sure what you are trying to achieve with the str_extract process but it > is looking for the exact string 'PDT2' the vectors / dataframe formed in > your previous commands are not being used at all. > Moving forward I think you need to pay attention to case "PD" != "pd". > Also the set PDT2 is going to be a subset of both sets PD and t2, I don't > think this is what you are after. > > On Mon, May 2, 2016, 8:49 AM <chalabi.el...@yahoo.de> wrote: > > Yes it works, but let me explain what I am going to do. I extract all the > names I want and then create a new column out of them for my plot. This is > he whole thing I do: > > PD=subset(df,grepl("pd",Command)) //extract names in Command with only > "pd" > > t2=subset(df,grepl("t2",Command)) //extract names with only "t2" > > PDT2=subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command) // extract > names which contain both "pd" and "t2" > > v1=c('PD','t2','PDT2')// I create a vector with these conditions > > str_extract(df$Command,paste(v1,collaps='|')) //returning patterns, > using stringr library > > > >here I see no pattern named PDT2 but there are only PD and t2 patterns. > >On Monday, May 2, 2016 8:18 AM, Tom Wright <t...@maladmin.com> wrote: > > > > > > > >Sorry for the missed braces earlier. I was typing on a phone, not the > best place to conjugate regular expressions. > >Using the example you provided: > > > >> df=data.frame(Command=c("_localize_PD", "_localize_tre_t2", > "_abdomen_t1_seq", "knee_pd_t1_localize", "pd_local_abdomen_t2")) > > > >> grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command) > >[1] FALSE FALSE FALSE FALSE TRUE > > > >> subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command)) > > Command > >5 pd_local_abdomen_t2 > > > > > > > >On Mon, May 2, 2016 at 7:42 AM, <chalabi.el...@yahoo.de> wrote: > > > >Thanks Peter, you were right, the exact grepl is > grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command), but it does not change > anything in Command, when I check the size of it by > sum(grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command)) the result is 0, but I > am sure that the size is not 0. It seems that this AND does not work. > >> > >> > >> > >>On Monday, May 2, 2016 5:05 AM, peter dalgaard <pda...@gmail.com> wrote: > >> > >>On 02 May 2016, at 12:43 , ch.elahe via R-help <r-help@r-project.org> > wrote: > >> > >>> Thanks for your reply tom. After using > Subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)"),df$Command) I get this error: > Argument "x" is missing, with no default. Actually I don't know how to fix > this. Do you have any idea? > >> > >>Tom's code was missing a ")" but not where you put one. He probably also > didn't intend to capitalize "subset". > >> > >> > >>-pd > >> > >>> Thanks, > >>> Elahe > >>> > >>> > >>> On Saturday, April 30, 2016 7:35 PM, Tom Wright <t...@maladmin.com> > wrote: > >>> > >>> > >>> > >>> Actually not sure my previous answer does what you wanted. Using your > approach: > >>> t2pd=subset(df,grepl("t2",df$Command) & grepl("pd",df$Command)) > >>> Should work. > >>> I think the regex pattern you are looking for is: > >>> Subset(df,grepl("(.* t2.*pd.* )|(.* pd.* t2.*)",df$Command) > >>> > >>> On Sat, Apr 30, 2016, 7:07 PM Tom Wright <t...@maladmin.com> wrote: > >>> > >>> subset(df,grepl("t2|pd",x$Command)) > >>>> > >>>> > >>>> > >>>> > >>>> On Sat, Apr 30, 2016 at 2:38 PM, ch.elahe via R-help < > r-help@r-project.org> wrote: > >>>> > >>>> Hi all, > >>>>> > >>>>> I have one factor variable in my df and I want to extract the names > from it which contain both "t2" and "pd": > >>>>> > >>>>> 'data.frame': 36919 obs. of 162 variables > >>>>> $TE :int 38,41,11,52,48,75,..... > >>>>> $TR :int 100,210,548,546,..... > >>>>> $Command :factor W/2229 levels > "_localize_PD","_localize_tre_t2","_abdomen_t1_seq","knee_pd_t1_localize","pd_local_abdomen_t2"... > >>>>> > >>>>> I have tried this but I did not get result: > >>>>> > >>>>> t2pd=subset(df,grepl("t2",Command) & grepl("pd",Command)) > >>>>> > >>>>> > >>>>> does anyone know how to apply AND in grepl? > >>>>> > >>>>> Thanks > >>>>> Elahe > >>>>> > >>>>> ______________________________________________ > >>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >>>>> https://stat.ethz.ch/mailman/listinfo/r-help > >>>>> PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > >>>>> and provide commented, minimal, self-contained, reproducible code. > >>>>> . > >>> > >>> ______________________________________________ > >>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >>> https://stat.ethz.ch/mailman/listinfo/r-help > >>> PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > >>> and provide commented, minimal, self-contained, reproducible code. > >> > >>-- > >>Peter Dalgaard, Professor, > >>Center for Statistics, Copenhagen Business School > >>Solbjerg Plads 3, 2000 Frederiksberg, Denmark > >>Phone: (+45)38153501 > >>Office: A 4.23 > >>Email: pd....@cbs.dk Priv: pda...@gmail.com > >> > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.